This article was first published in the November
2006 issue of The Cartridge Researcher,

the journal of the European Cartridge Research
Association.

Readers of my science-fiction novel Scales will recall this gun featuring in it,
and might like to see what it actually looks like!

Amended with additional information
from the designer, Tony Neophytou, on 30 August 2007

and with further changes on 25 January
2009

The choice in shoulder guns firing HE shells of at least 20
mm calibre continues to grow. Already available are some rifles such as the
South African Mechem NTW which fires old
cannon cartridges, namely the 20x82 (MG 151) and 20x110 (Hispano HS 404), and a
newer rival from the same country, the Truvelo (20x110). Also being developed is
the Barrett XM109 "Payload Rifle" in the same 25x59B calibre used for the XM307 ACSW (Advanced Crew Served Weapon
- now cancelled) and the XM25 which
fires shorter (25x39B) ammunition. Already available is the RAG-30 from
the Slovak Republic, an 11.7 kg rifle firing the Russian 30x29B grenade round,
and lightweight Chinese 35mm weapons. And of course there are many shoulder guns
for the western 40x46SR LV (Low Velocity) grenade round (and the more recent
Medium Velocity loading of that cartridge), in the form of under-barrel
launchers attached to rifles and stand-alone single-shot or six-shot revolvers.

Now there is a new offering from South Africa; the Neopup
P.A.W. (Personal Assault Weapon), also known as the PAW-20. This introduced its own 20x42 cartridge made by PMP –
Denel Munitions. Originally rimless, this was in 2008 replaced by a belted
version. The explanation for this is that chamber location was originally
provided by a pin protruding through the chamber wall which locked into the
extractor groove. While this worked for steel-cased ammo, Neopup intends to
develop plastic-cased less-lethal ammo, and the plastic cases were not strong
enough for this, so the belt now locates the round.

The cartridge is something of a hybrid, because it
fires normal 20mm HEI cannon projectiles, but from a very small case to
keep the velocity down. It is a direct-fire weapon, with (so far) no
plans for the complex airburst fuzing technology used in the XM25. The
principal advantage of the ammunition is that its higher muzzle
velocity of 305 m/s and more aerodynamic projectiles permit a much
flatter trajectory and shorter flight time than the usual 40mm LV
round. At a range of 300 metres, for instance, the 20x42 projectile
takes 1.07 seconds to reach the target, with a mid-range vertex
(maximum trajectory height) of 1.4 metres. Comparable figures for the
40mm LV (76 m/s muzzle velocity) are 4.66 seconds and 26 metres. The
new 40mm MV rounds (around 100-120 m/s) will approximately halve the
LV's figures, but it will still be far more difficult to hit a point
target with the 40mm shoulder-fired weapons. This ballistic performance
gives the PAW-20 an effective range against point targets of 600m, with
suppressive fire up to 800m and fire against area targets at up to
1,000m. Obviously, a laser rangefinder built into the sights would
greatly enhance the first-round accuracy at long range.

The gun is also interesting. It is gas operated with a
rotating bolt, and fed by a 7-round detachable box magazine (in the initial
version this was single-stack but the latest model has a double-stack magazine
in the interests of compactness). Another recent change has been the addition of
a muzzle brake to compensate for muzzle flip and allow faster repeat shots. The barrel and action are
designed to recoil about 75mm into the stock to soften the recoil blow. To
enable this to happen, the pistol grip is on the right hand side of the gun,
allowing the action to recoil past it. This feature also enables the gun to be
telescoped slightly to make a more compact package for transportation, with the
overall length reduced from 860mm to 785mm. Gun weight is 5.7 kg (12.6
lbs) which is a manageable weight for carrying. It can be fired from the
left shoulder simply by shifting the butt over to that side, while keeping the
hands in the same position.

To sum up, this weapon has a unique combination of
attributes. Small and light enough to be carried instead of a rifle as a primary
arm, it offers far more accuracy and rate of fire than any other weapon with
comparable destructive effect, with the presumed exception of the XM25, which is
likely to be far more expensive (both gun and ammunition) in view of its
sophisticated electronic systems.

Below are some photos of an earlier version of the gun. The
current one is illustrated in the official brochure (see link below).

And this shows a novel form of promoting the weapon: a salt & pepper set,
using actual projectiles with purpose-made solid-base cases!

Official information on the gun and ammunition, plus a video, can be found HERE